The present technology relates to a storage media device that is capable of storing encrypted user data and a recording apparatus that supplies user data to the storage media device.
For storage media managed by a general file system, even when a recorded file is deleted according to an instruction from a user, only an index indicating the location where the actual data is recorded is deleted and the actual data still remains in the storage medium. Thus, the data could be retrieved through analysis of the storage medium. A typical method for erasing data recorded in a storage medium so that the data is unrecoverable is to overwrite the data in the storage medium with dummy data having a size that is equivalent to the capacity of the storage medium.
However, such an overwriting-based data erasing method takes a certain amount of time. Complete erasure of the user data in the storage medium in a short period of time by a simple operation is demanded, for example, in the following situations.
For example, in the field of mineral or oil-source explorations, survey data are collected at surveyed locations through various techniques. In such explorations, for example, transportations, such as an airplane and an automobile are often used, which may involve physically dangerous work. Thus, there may even a situation in which the user has to discard the storage medium in which the collected survey data are stored. In such a situation, in order to prevent leakage of the collected survey data, it is desired to provide measures that allow the user who owns the storage medium to easily and completely erase the data in the storage medium himself or herself as quickly as possible.
Examples of the storage media include magnetic tapes, HDDs (hard disk drives), and semiconductor memories, such as flash memories. In the case of magnetic tapes, application of a strong magnetic force destroys magnetic signals recorded on the media to thereby completely erase the data in the media. Recently, however, storage media employing HDDs or semiconductor memories are increasingly used because of their higher speeds, small sizes, ease of connection with other equipment, and so on.
For HDDs or semiconductor memories, it is not easy to completely erase recorded data, unlike the case of the magnetic tapes. This is because it is difficult to externally apply magnetic forces to the main bodies (i.e., magnetic disks) of the HDDs since the main bodies are accommodated in metal casings, though the HDDs are similar to the magnetic tapes in that both are magnetic media. On the other hand, semiconductor memories, such as flash memories, are not magnetically destroyed because of the structure of their storage elements.
Japanese Unexamined Patent Application Publication No. 2009-277085 discloses a technology for an information-deletion-function-equipped LSI having a circuit for erasing the contents stored in a memory. The LSI disclosed in Japanese Unexamined Patent Application Publication No. 2009-277085 has therein electricity-generating means, which generates electrical energy to operate deleting means and detecting means. Upon detecting a change in information which is caused by an external attack, the detecting means issues an instruction for deleting the contents of the memory to the deleting means and the deleting means deletes the contents in accordance with the instruction.